The correlation of γ-irradiation, particle size and their effects on physical properties of AgInSe2 nanostructure thin films

In this work the effect of gamma-irradiation on the optical and electrical properties of near stoichiometric AgInSe2 nanostructure thin films have been characterized. The XRD pattern of ingot AgInSe2 powder prepared by solid state reaction showed tetragonal polycrystalline single-phase structure. The thin films of thickness 75 nm were prepared by inert gas condensation (IGC) technique at using constant Ar flow and substrate temperature of 300 K.Thin films were exposed to annealing process at 473 K for 2 h in vacuum of 10(-2) Torr. The amorphous and tetragonal nanocrystalline structures were detected for as deposited and annealed films respectively by grazing incident in-plane X-ray diffraction (GIIXD) technique. The structure and average particle size of annealed irradiated films by different gamma-doses from 0 to 4 Mrad were determined using high resolution transmission electron microscope (HRTEM). Optical transmission, reflection and absorption spectra were studied for both annealed unirradiated and irradiated films. Two optical transitions for each annealed unirradiated and film exposed to gamma-irradiation doses from 0 to 4 Mrad were observed. The evaluated E-g1 due to 1st transition have decreased from 1.52 to 1.44 eV and E-g2 due to 2nd transition have decreased from 2.83 to 2.30 eV as the particle size increased from 7.3 to 9.5 nm by raising the irradiation dose up to 1 Mrad. The behavior of d.c. electrical conductivity with temperature that measured under vacuum was examined for all films under investigation. The evaluated activation energies due to irradiation doses are ranging from 0.58 to 0.68 eV. (C) 2016 Elsevier Ltd. All rights reserved.